1) Abecedarian 2) Abortive 3) Basal 4) Basic 5) Crude 6) Embryonic 7) Inchoate 8) Incomplete 9) Uncomplete 10) Undeveloped 11) Vestigial 1) Abecedarian 2) Basic 3) Essential 4) Fundamental 5) Of the nature of a rudiment 6) Primitive 7) Underlying 8) Undeveloped or vestigial 
poorly developed and not functional; compare vestigial.
imperfectly developed
• (a.) Of or pertaining to rudiments; consisting in first principles; elementary; initial; as, rudimental essays. • (a.) Very imperfectly developed; in an early stage of development; embryonic.
Poorly or imperfectly developed.
Poorly developed and not functional. ... Compare: vestigial, obsolete. ... (09 Oct 1997) ... 
(roo″dĭ-men´tә-re) imperfectly developed. vestigial.
Ru`di·men'ta·ry adjective [ Confer French rudimentaire .] 1. Of or pertaining to rudiments; consisting in first principles; elementary; initial; as, rudimental essays. 2. (Biol.) Very imperfectly developed; in an early stage of development; embryonic. 
Incomplete; very little developed.
Type: Term Pronunciation: rū′di-men′tă-rē Definitions: 1. Relating to a rudiment. Synonyms: abortive2
imperfectly developed
[adj] - being in the earliest stages of development
rudimentary, rudimental 1. Pertaining to rudiments or first principles; elementary; such as a rudimentary knowledge of English. 2. Of the nature of a rudiment; undeveloped or vestigial (visible evidence of something that is no longer present or in existence). 3. Primitive.
adjective being in the earliest stages of development; `rudimentary plans`
pertaining to rudiments or first principles; elementary: a rudimentary knowledge of geometry. · of the nature of a rudiment; undeveloped or vestigial. · primitive.
[SAT terms] being in the earliest stages of development[ACT vocabulary] being in the earliest stages of development